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 * Author: Eitan Marder-Eppstein
 *         David V. Lu!!
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#ifndef COSTMAP_2D_COSTMAP_LAYER_H_
#define COSTMAP_2D_COSTMAP_LAYER_H_

#include <ros/ros.h>
#include <costmap_2d/layer.h>
#include <costmap_2d/layered_costmap.h>

namespace costmap_2d
{
// costmap_layer同时继承了layer和costmap2D类，最主要的作用就是更新地图层的代价值。
// 它是地图插件（静态层和障碍层）的基类。它的类方法主要用于处理bound和用几种不同的策略合并子地图和主地图。

class CostmapLayer : public Layer, public Costmap2D
{
public:
    CostmapLayer() : has_extra_bounds_(false),
                     extra_min_x_(1e6), extra_max_x_(-1e6),
                     extra_min_y_(1e6), extra_max_y_(-1e6) {}

    bool isDiscretized() { return true; }

    virtual void matchSize();

    virtual void clearArea(int start_x, int start_y, int end_x, int end_y, bool invert_area = false);

    /**
     * If an external source changes values in the costmap,
     * it should call this method with the area that it changed to ensure that the costmap includes this region as well.
     * @param mx0 Minimum x value of the bounding box
     * @param my0 Minimum y value of the bounding box
     * @param mx1 Maximum x value of the bounding box
     * @param my1 Maximum y value of the bounding box
     */
    void addExtraBounds(double mx0, double my0, double mx1, double my1);

protected:
    /* 用当前子地图数据（包括未知cell）覆盖主地图对应区域
     * Updates the master_grid within the specified bounding box using this layer's values.
     * TrueOverwrite means every value from this layer is written into the master grid.
     */
    void updateWithTrueOverwrite(costmap_2d::Costmap2D &master_grid, int min_i, int min_j, int max_i, int max_j);

    /* 用当前子地图数据（不包括未知cell）覆盖主地图对应区域
     * Updates the master_grid within the specified bounding box using this layer's values.
     *
     * Overwrite means every valid value from this layer
     * is written into the master grid (does not copy NO_INFORMATION)
     */
    void updateWithOverwrite(costmap_2d::Costmap2D &master_grid, int min_i, int min_j, int max_i, int max_j);

    /* 用当前子地图数据（不包括未知cell）更新主地图对应区域
     * Updates the master_grid within the specified bounding box using this layer's values.
     *
     * Sets the new value to the maximum of the master_grid's value and this layer's value.
     * If the master value is NO_INFORMATION, it is overwritten.
     * If the layer's value is NO_INFORMATION, the master value does not change.
     */
    void updateWithMax(costmap_2d::Costmap2D &master_grid, int min_i, int min_j, int max_i, int max_j);

    /* 用当前子地图数据（不包括未知cell）更新主地图对应区域
     * Updates the master_grid within the specified bounding box using this layer's values.
     *
     * Sets the new value to the sum of the master grid's value and this layer's value.
     * If the master value is NO_INFORMATION, it is overwritten with the layer's value.
     * If the layer's value is NO_INFORMATION, then the master value does not change.
     *
     * If the sum value is larger than INSCRIBED_INFLATED_OBSTACLE,
     * the master value is set to (INSCRIBED_INFLATED_OBSTACLE - 1).
     */
    void updateWithAddition(costmap_2d::Costmap2D &master_grid, int min_i, int min_j, int max_i, int max_j);

    /** 更新参数中指定的边界框，以包含位置(x,y)
     * Updates the bounding box specified in the parameters to include the location (x,y)
     *
     * @param x x-coordinate to include
     * @param y y-coordinate to include
     * @param min_x bounding box
     * @param min_y bounding box
     * @param max_x bounding box
     * @param max_y bounding box
     */
    void touch(double x, double y, double *min_x, double *min_y, double *max_x, double *max_y);

    /* 更新参数中指定的边界框，以包括来自adddextrabounds调用的边界框。
     * Updates the bounding box specified in the parameters to include the bounding box from the addExtraBounds call.
     * If addExtraBounds was not called, the method will do nothing.
     * Should be called at the beginning of the updateBounds method
     *
     * @param min_x bounding box (input and output)
     * @param min_y bounding box (input and output)
     * @param max_x bounding box (input and output)
     * @param max_y bounding box (input and output)
     */
    void useExtraBounds(double *min_x, double *min_y, double *max_x, double *max_y);

    bool has_extra_bounds_;

private:
    double extra_min_x_, extra_max_x_, extra_min_y_, extra_max_y_;
};

}  // namespace costmap_2d
#endif  // COSTMAP_2D_COSTMAP_LAYER_H_
